The present invention relates to a fluid flow reversing and regulating ring for a fluid mechanism and in particular to an exhaust flow reversing and regulating ring for a handheld pneumatic power tool.
For some pneumatic power tools it is desirable to have a rear exhaust flow, while for other pneumatic tools it is desirable to have a front exhaust flow to clean the working area, for example. Some conventional tools use a valve to reverse the flow of exhaust fluid. Other known tools are constructed solely for front exhaust or rear exhaust.
The disadvantage of a reversing valve mechanism is the complex construction, assembly, and high cost. Also the valve may permit leakage due to wear of the valve parts or incomplete closure. The disadvantage of the permanently front or rear exhausted tools is difficulty of conversion for alternate exhaust. Also, additional single use parts must be produced for each exhaust alternative.
Closely related to the exhaust configuration problem is the desirability of obtaining different motor speeds for the same motor construction. Typically this can be done by sizing and shaping an orifice in the fluid flow path to restrict fluid flow to a predetermined mass rate of flow, thus limiting motor speed. Again, speed regulation can be accomplished with a variable regulating valve or alternatively, with many single use permanent parts.
However, the disadvantages of the known speed regulating devices are similar to the flow reversing problems. A regulating valve is complex and subject to wear and partial operation. Permanent parts reduce the flexibility of converting the tool and create logistical problems in manufacturing the various parts. Both alternatives are costly to construct.